Continuous process for the production and treatment of artificial threads and apparatus therefor



Oct. 17, 1950 s. w. BARKER ETAL 2,525,

CONTINUOUS PROCESS FOR THE PRODUCTION AND TREATMENT OF AR 'IIFICIAL THREADS AND APPARATUS THEREFOR I Filed Jan. 13, 1948 2 Sheets-Sheet 1 SYDNEY WARRENBARKER Inventor-.5 6:02: 5 Lcon'am Goomrm Oct. 17, 1950 s w. BARKER ETAL 2,526,110

CONTINUOUS PROCESS FOR THE PRODUCTION AND TREATMENT OF ARTIFICIAL THREADS AND APPARATUS THEREFOR Filed Jan. 13, 1948 2 Shgets-Sheei 2 llllll I ill 1,1,,

SYDNEY WARRE M BflRkeR Geonee LEONARD Goomm I nventors A lorney Patented Oct. 17, 1950 UNITED STATES PATENT OFFICE Sydney Warren Barker, Colne, and George Leonard Godman, Thornton on-Oraven,

Skipton,

England, assigno'rs to Lustrafil Limited, Nelson,

England Application January 13, 1948, Serial No. 1,984

8 Claims.

1 This invention relates to continuous processes for the spinning and treatment of artificial threads in which the thread issuing from the spinneret traverses a pair of thread-storing, thread-advancing skew rollers in the form of helical loops, and in particular, to continuous processes and apparatus for the spinning and treatment of the type of artificial thread known as strong yarn, and especially strong yarn for fine textile purposes. It is particularly, concerned with methods of starting up such processes either initially or after a break. In the production of high tenacity yarn by the viscose process, it is well known to extrude viscose through a' spinneret into an acid setting bath containing a relatively high percentage of zinc sulphate, e. g. 4-7%, and then after a suitable length of run,'to pass the yarn through a bath of hotacid or water at 80-100 C. Whilst at" the same time subjecting the thread to a stretching of -80% of its length.

-In' operating in this way, it is usual to take.

the thread from the acid coagulating bath to a godet round which it is passed several times, and then after passing through the hot acid, the thread is taken to another godet with a peripheral speed higher than that of the first godet,

and round which it is passed several times in order to prevent any possibility of slipping, before being taken up in a collecting device such as a Topham box.

- When thismethod of stretching is used in of the thread on a pair of skew rollers, the starting up of the whole process presents considerable difficulty. Usually the thread is taken from the acid coagulating bath several times round a godet and then into a hot bath placed behind thefirst bathwThe thread is then taken up to the skew rollers, whose peripheral speed is higher than that of the godet in order to develop the stretch.

If. however, any slack is allowed to develop between the godet and the skew rollers, the thread winds itself continuously round the godet and so the process of starting up has to be commenced again. Since the godet is delivering thread at the rate of approx. 40-50 yards per minute, it can.be realised that it is a very difficult matter to start the thread on to the skew rollers without allowing any slack to develop.

. Alternatively the thread is sometimes started up directly on to the skew rollers and afterwards the thread is guided several times round the godet and passed through the hot bath. This process is again very difficult since the thread becomes tightly stretched on passing over the godet, and the thread is often broken in passing itseveral timesround the godet and in guiding it into the hot bath, especially in the case of fine taken round the godet after the start-up.

conjunction with further continuous treatment We have now devised an easy method of starting up which avoids these inconveniences. For this purpose we make use of a godet of such diameter and having such a surface that the wet thread slips easily over it at all contact angles up to about 180 but does not slip, even under considerable tension, when the contact angle is in theregion of 350. By contact angle we mean the angle'representing the change of direction of the threadproduced by th interposition of thegodet.

We have found, for example, that a godet of about 6 inches diameter and having a surface of smooth ebonite without serrations exerts the necessary grip on wet viscose thread at acontact angle of 300 to 360, whilst allowing free slipping at a contact angle of 180 or less. The same effect is observed with surfaces of glazed, fine matt or matt porcelain so long as the surface of the godet is thoroughly wet with the coagulating liquor. Naturally the surface must not be so rough as to tear the individual filaments of the thread. Within this limitation the factors determining slipping or gripping of the thread are the diameter of the godet and the contact angle, variations such as those mentioned above in the smoothness of the surface being of little account if the surfac is thoroughly wet with the liquor. sured by an initial flooding of the surface of the godet with the coagulating liquor, but this is usually unnecessary, sufficient liquor for the purpose being carried up by the thread emerging from the coagulating bath. The addition of a small proportion (e. g. 0.02%) of a wetting agent such as Perminal W (Perminal is a registered trade-mark) to the coagulating'liquor ensures easy wetting of the godet and renders initial flooding quite unnecessary.

Where only a small extension of the thread 5 (e. g. 10-25% is desired, the tension is low and a godet of smaller diameter, e. g. 4-5 inches, is

found to exert the necessary grip on the thread at a contact angle of 300-360 whilst allowing slippage at a contactangle'of 180 or less.

Even with tensions high enough to produce extension of the thread, although larger godets may be used if desired, there is no advantage in a diameter greater than about 6 inches. Larger godets tendto grip the thread even at a contact angle of and at 350-360 the gripping is unnecessarily heavy for the purpose.

By the use of a going description godet conforming to the forewe' are enabled, by appropriate adjustment of the angle of contact, to bring about This wetting may, if .desired, be enslippage or gripping of the thread as desired, and it is the application of this discovery which constitutes our invention.

According to the invention we provide a method and apparatus for starting up a continuous process for the spinning and treatment of artificial threads, particularly applicable to the spinning and treatment of strong yarn, the method comprising three steps, each occupying only a few seconds, a godet conforming to the foregoing description being employed. These steps will now be described with reference to the accompanying drawings which illustrate the invention diagrammatically.

Figs. 1, 2 and 3 show the position of the thread after the first, second and third steps, respectively, in the preferred embodiment of the invention, in which deep, somewhat narrow baths are used for coagulation and for treatment with hot water or acid.

Filaments issuing from the spinneret l immersed in the coagulating bath 2 pass at the first of the three stages direct to the pair of skew rollers 3, 4 which they join a few inches from the initial (forward) end (to the left in Fig. l) the thread is carried round the pair of rollers in successive helical turns in the known manner, and after traversing the rollers to the further end is collected.

In the second step the thread is engaged by a freely rotating runner 6 and drawn to the left over the godet 5 and down into the hot bath 1, in which the runner 6 now takes up a permanent position 8. During this operation the thread fills up the few inches at the forward end of the pair I of rollers and assumes the position shown in Fig. 2. If desired, the thread during this operation may be directed to its new position on the rollers by means of a guide bar, which may be made from glass rod. The contact angle, i. e. the change of direction of the thread as it passes over the godet, approaches 180, and accordingly at this stage there is as much slippage of the thread on the godet as may be needed to prevent the thread wrapping itself round the godet.

In the third and last step a second freely rotating runner 9 or [0 is applied to the thread below the godet so as to increase the contact angle to about 330-360". If runner 9 is used, it is moved to the left; if runner I0 is used, it is moved to the right. We prefer to employ a pair of runners 9 and [0, each increasing the angle of contact 80-90", so that the final angle of contact when the two runners are side by side, as shown in Fig. 3, is about 330-360. The godet is now able to grip the thread and the operation of starting-up is complete.

The essentials for the method of starting-up according to our invention are a godet of such diameter and surface as will allow slippage or ensure gripping of the thread according as the angle of contact is small (up to 180) or large (300-360), and either two or three freely rotating runners. One runner takes the thread (after it has been started directly on a pair of skew rollers) round the godet and into the hot bath. In the embodiment shown in Figs. 1, 2 and 3 this runner (6) itself constitutes the guide (8) for the thread in the hot bath; but if desired a fixed guide 8 may be used and the runner 6 returned to its initial position (Fig. 1) after conducting the thread round the fixed guide 8 in the hot bath. The function of the second and third runners 9, I0 is to increase the angle of contact to a degree suflicient to ensure gripping of the thread by the godet. Fig. 4 shows on a larger scale in end elevation the side-by-side position of the runners 9, II] at the stage represented in Fig. 3. If desired, the runners 9, l0 may be taken to positions such as those shown in Fig. 5. Although We prefer to use two runners; a similar increase in the angle of contact may be obtained by the use of one runner, which may be applied to the upward-moving thread as shown in Fig. 6, or correspondingly to the downward-moving thread. It is obvious that in place of the freely rotating runners 6, 9, l0 movable low-friction guides may be used without departing from the invention. The runner or guides 9, 10 are preferably applied to the thread close below the godet so as to achieve the increase of the angle of contact with a small change in position of the runners.

The godet 5 is a roller, driven at a peripheral speed 10-80% less than that of the (pair of skew rollers 3, 4 and may be short, supplying only one pair of skew rollers, or, more usually, it may be extended in length so as to supply two, three or more pairs of skew rollers, each pair being provided with separate spinneret, runners and guides. The two baths also may extend the whole length of the unit comprising a number of pairs of skew rollers.

The disposition of the baths, the skew rollers, the godet and the moveable runners need not be that represented in Figs. 1-3, but may be varied to suit the general layout of the plane. It may, for example, be desired to situate the godet between the two baths at the same level as the baths or below them. In that case additional guides will be necessary and the second (or second and third) runner will be applied to the thread above the godet. Such an arrangement is illustrated in Figs. 7, 8 and 9 which show the two baths and the godet but not the rollers. The filaments issuing from the spinneret l are taken from the coagulating bath 2 via fixed guides H and 12 direct to the pair of skew rollers in the first stage. Next the runner 6 is engaged with the thread above guide l2 and takes it via fixed guide l3 round underneath the godet 5 and thence over guide !4 and into the hot bath 1 where the runner takes up the position 8 and the thread passes to the skew rollers. In the third step runners 9 and I0 take the thread to the left and right, respectively, so as to increase the angle of contact with the godet sufficiently to ensure gripping, and the operation of starting-up is complete. Where the godet is so situated, however, a separate drive becomes necessary for each godet in order that the thread may be taken round it, and one of the advantages, of the invention is thus lost.

Corresponding variations in the application of our invention may be made to suit other positions of the godet relative to the two baths and the pair of skew rollers.

The advantages of the invention will be clear from the foregoing description. Since at the time when slack might develop the angle of contact is such as to allow slippage, no wrapping of the thread several times round the godet can occur. The thread never makes more than a single turn round the godet, and at the end of the second step in the operation of starting up its contact with the godet is not more than half a turn.

In a typical arrangement according to the preferred embodiment of the invention, a LO-filament thread of denier is spun from a viscose solution (7% cellulose and.6% alkali, by weight) into a coagulating bath containing 8.5% sulphuric acid V 18.0% sodium sulphate (anhydrous) 4.0% Zinc sulphate (anhydrous) 1.0% glucose 0.02% Perminal W the remainder being water. The thread run from the spinneret nozzle to the godet is 15 inches. The godet has a diameter of 6% inches, and the angle of contact is 180 on starting and 345 on completion of the starting operation as 1 described with reference to Figs. 1, 2 and 3. The

thread travel from the godet to the upper of the pair of skew rollers is 45 inches including the passage through the hot bath, .which is water at 85 C. containing percentages are by weight. During its traverse of the skew rollers the thread is washed and dried in the usual manner, and at the end of its traverse it is collected on cap spinner or ring spinner bobbins.

We claim:

1. Apparatus for the continuous production and treatment of artificial threads of the type known as strong yarn comprising in combination a spinneret located in a spinning bath of coagulating liquid, a hot treatment bath, a godet, suitably situated between the spinning bath and the hot treatment bath, a pair of thread-storing, thread-advancing rollers which the thread traverses in helical loops in known manner, the said rollers rotating at a peripheral speed suitably greater than that of the godet for the purpose of stretching the thread to the desired extent, together with (a) means for diverting the thread from a path directly between the spinneret and the rollers to the path via the godet and the hot treatment bath to the rollers, and (b) means for diverting the thread from itspath near to the godet-so as to vary the contact angle of the thread with the godet, the diameter and surface of the godet being so chosen as to allow slippage of the thread at contact angles of less than about 180 whilst ensuring gripping of the thread at contact angles greater than about 300.

2. Apparatus as claimed in claim 1 in which the godet has a diameter of about 6%, inches and a surface selected from the group consisting of smooth ebonite, glazed porcelain, fine matt porcelain and matt porcelain.

1.7% of sulphuric acid. All

3. Apparatus as claimed in claim 1 in which 7 the means for diverting the thread from its path consists of suitably mounted freely rotating runners.

4. Apparatus as claimed in claim 1 in which the means for diverting the thread from its path near the godet so as to vary the contact angle of the thread with the godet consists of two lowfriction guides which are movable to engage the thread on opposite sides of the godet.

5. Apparatus for producing and treating artificial thread which comprises the combination, with a spinning bath, a' spinneret discharging thereinto, and thread-storing, thread-advancing means adapted to receive and advance thread from said bath, of a treating bath, guide means adapted and arranged to direct a thread issuing from said spinning bath into said treating bath and thence to said storing and advancing means,

said guide means including a thread-gripping member located outside both said baths and a guide member movable, upon starting up the apparatus, from a position outside both said baths and between them and said storing and advancing means against the thread, at a point in its traverse that is between said thread-gripping member and said storing and advancing means, to move the thread initially into slippingengagement with said thread-gripping member and to a position of submergence in said treating bath; and further guide means movable against the thread to change said slipping engagement of the thread with the thread-gripping member into gripping engagement.

6. The method of starting up a process for the spinning and treatment of artificial threads, which comprises initially leading the thread from a spinning bath directly into engagement with thread-advancing, thread-storing means so that the thread is thereupon drawn by said means directly from said spinning bath, then diverting the thread at a point in its traverse intermediate said bath and said advancing and storing means into slipping engagement with thread-gripping means and thence into a succeeding treating bath before it goes to said advancing and storing means, and then adjusting the engagement of the thread with said gripping means to eifect operative gripping of the thread thereby.

7. The method of conducting a thread initially to its appropriate path in a process for the production and treatment of artificial threads, which comprises the successive steps of: (a) conducting the thread from a spinning bath directly to means for storing and advancing the thread, (12) diverting the thread from its path between said spinning bath and said advancing means to a second path from the spinning bath, into slipping contact with a thread-gripping member, thence into a hot treatment-bath and thence to said storing and advancing means, and (0) further diverting the thread adjacent said gripping member so as to increase the contact of the thread with said gripping member sufficiently to ensure gripping of the thread thereby.

8. The method of conducting a thread initially to its appropriate path in a process for the production and treatment of artificial threads, which comprises the successive steps of: (a) leading the wet thread from a spinning bath directly on to a pair of thread-storing, thread-advancing rollers,

round which it is conducted by known means,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,108,188 I Batchelder Feb. 15, 1938 2,141,544 Marzari Dec. 27, 1938 2,348,415 Polak May 9, 1944 2,459,254 Van Der Mei Jan. 18, 1949 

6. THE METHOD OF STARTING UP A PROCESS FOR THE SPINNING AND TREATMENT OF ARTIFICIAL THREADS, WHICH COMPRISES INITIALLY LEADING THE THREAD FROM A SPINNING BATH DIRECTLY INTO ENGAGEMENT WITH THREAD-ADVANCING, THREAD-STORING MEANS SO THAT THE THREAD IS THERUPON DRAWN BY SAID MEANS DIRECTLY FROM SAID SPINNING BATH, THEN DIVERTING THE THREAD AT A POINT IN ITS TRAVERSE INTERMEDIATE SAID BATH AND SAID ADVANCIUNG AND STORING MEANS INTO SLIPPING ENGAGEMENT WITH THREAD-GRIPPING MEANS AND THENCE INTO A SUCCEEDING TREATING BATH BEFORE IT GOES TO SAID ADVANCING AND STORING MEANS, AND THEN ADJUSTING THE ENGAGEMENT OF THE THREAD WITH SAID GRIPPING MEANS TO EFFECT OPERATIVE GRIPPING OF THE THREAD THEREBY. 